The use of exchange coupling between ferromagnets and antiferromagnets (AFM) or artificial antiferromagnets (AAF) to secure magnetizations in magnetic layer systems is known.
In most cases components in magnetic sensor technology or spin electronics require a fixed reference magnetization direction. To this end the magnetic coupling to a so-called “anchor layer” is frequently utilized. This anchor layer can comprise a hard magnet, a natural or artificial antiferromagnet. The magnetization direction of the ferromagnetic layer is spatially fixed through the exchange coupling between ferromagnet and anchor layer.
This anchor layer itself must likewise be magnetically aligned. To this end, depending on the material properties of the anchor layer, until now the following processes have been used:                Layer deposition in an external magnetic field        Thermal aftertreatment in an external magnetic field        Field cooling after local laser irradiation        
In all three cases an effective field cooling is carried out, i.e., the ferromagnet/anchor layer system is transferred from a state above the critical coupling temperature (blocking temperature TB) with applied magnetic field to a coupled state. Thus a homogenous magnetization of the ferromagnetic layer forced by the magnetic field is impressed by direct exchange coupling into the spin configuration of the antiferromagnetic layer. For external field strengths below the coupling field strength, the adjusted homogenous magnetization of the ferromagnetic layer is maintained and thus serves as reference magnetization.
Of the processes listed above, only the last one is able to locally change reference magnetizations in the area of the focus of a laser beam.
The disadvantages of the known processes are that, with the exception of the laser process, it is impossible to realize several reference directions in any directions to one another at the same time. This is necessary for the functionality of more complex magnetoelectronic components, such as, e.g., angle sensors.
And finally subsequent process steps for aligning the AFM are necessary and complicated and only to a certain extent compatible with the microminiaturization.
It is further known that in soft-magnetic layer elements the magnetization is orientated along the element edges in order to avoid stray fields. The magnetic flux thus provides a closed configuration. As van den Berg discovered, the magnetization also remains parallel to the nearest element edge in the interior of the element. In points that have the same distance to two element edges, the different magnetic areas collide. A state thus arises with homogenous magnetic domains that are separated by domain walls.
It is known that elements separated from one another by a sufficiently small distance interact with one another via their stray area. In order to achieve a state that is favorable in energy terms, neighboring elements adopt magnetization configurations that are close to a closed magnetic flux and cause only small stray fields.